1. Field of the Invention
The present invention relates to a dishwasher, and more particularly, to a dishwasher having a simple structure and an improved function of filtering washing water.
2. Description of the Prior Art
A dishwasher is an appliance for automatically washing the dishes by spraying detergent-mixed washing water. The dishwasher having a variety of structures and shapes has been proposed. Hereinafter, the constitution of such conventional dishwasher will be briefly explained.
FIG. 1 is a view illustrating the constitution of the conventional dishwasher.
Referring to FIG. 1, the conventional dishwasher includes a case 10, a rack 20 installed in the case 10 for accommodating the dishes, a spray arm 30 installed below the rack 20, a circulation pump 40 for pressurizing and supplying washing water to the spray arm 30, a drain pump 50 for draining the washing water, a filtering means for filtering the washing water, and the like.
Further, the spray arm 30 is horizontally rotatably supported by an arm holder 32 and is provided thereon with a plurality of spray nozzles 301 facing the rack 20. Furthermore, the circulation pump 40 is constructed such that a discharge port thereof is connected to the arm holder 32 and an inlet port thereof is connected to a water collector 60 for constructing the filtering means.
The filtering means includes the water collector 60 disposed below a bottom surface of a case 10, and a primary filter (coarse filter) 62 and a secondary filter (fine filter) 64 which are installed in the water collector 60. A top face of the water collector 60 is opened toward a so-called washing space, a side face thereof is connected to the circulation pump 40, and a bottom face thereof is connected to the drain pump 50. The secondary filter 64 is constructed in the form of a pipe such that a lower part thereof can communicate with the drain pump 50, and the primary filter 62 is constructed in the form of a filtering net provided within the secondary filter 64.
The operation of the conventional dishwasher as described above can be broadly divided into a washing step and a drain step, and can be performed according to these steps. In the washing step, washing water in which pure water and detergent are mixed together is pressurized and supplied to the spray arm 30 by the circulation pump 40. The washing water is then sprayed, through the spraying nozzles 301, on the dishes d seated on the rack 20. Consequently, the operation of washing the dishes d can be performed. Furthermore, in the drain step, the washing water can be discharged by the operation of the drain pump 50.
FIG. 2 is a view illustrating a filtering process of the conventional dishwasher.
Referring to FIGS. 1 and 2, the washing and drain operations thereof will be explained in detail. As shown in FIG. 2, the washing water sprayed from the spray arm 30 is subject to a circulation operation that it is collected into the water collector 60 disposed on a lower portion of the case and then supplied again to the spray arm 30 by the circulation pump 40. While the washing water is circulated, garbage such as food particles separated from the dishes d is filtered out or strained out by the primary and secondary filters 62, 64 installed in the water collector 60, and thus, the washing water can be prevented from being dirty. Furthermore, at this time, the drain pump 50 should be not operating to prevent the washing water from draining.
The drain step progresses after the washing step for a predetermined period of time has been completed. In the drain step, the washing water is discharged by the operation of the drain pump 50. At this time, a part of garbage particles that are large are filtered out by the primary filter 62 preventing a drain port from clogging. The filtered food particles remain in the primary filter 62. Further, garbage, of which particles are small and has not been filtered by the primary filter 62 are filtered by the secondary filter 64, and discharged together with the washing water through the drain port of the drain pump 50.
While washing the dishes, a round of the washing/drain step can be performed by only a so-called single filling-up of the water. In general, during one round of washing the dishes, three or four times of filling-up of the water and subsequent washing/drain steps can be performed in order to enhance efficiency of washing the dishes.
However, the conventional dishwasher described above has required both the circulation pump 40 for use in the washing and rinsing processes and the drain pump 50 for use in the draining process. Therefore, there are problems in that the structure thereof is complex and the production costs thereof are high.
Further, according to the conventional dishwasher, the garbage adheres to the secondary filter 64 from the viewpoint of the structural nature of the secondary filter 64 (i.e., fine filter has fine meshes), and the garbage adhered thereto is not smoothly discharged during the drain step. Thus, newly supplied washing water may be contaminated. Accordingly, there are problems in that washing efficiency is reduced and the garbage adhered to the secondary filter deteriorates circulation efficiency of the newly supplied washing water.
Furthermore, after the washing process has been finally completed, the garbage filtered out by the respective filters 62, 64 should be removed. However, the garbage filtered out by the primary filter 62 is easily removed since the particles thereof are relatively large, whereas the fine garbage caught in the secondary filter 64 is not easily removed. Therefore, the problem that convenience of use is lowered is produced.
The present invention is contemplated to solve the above problems in the prior art. The present invention newly proposes a flow passage, a pump and a filtering structure of a dishwasher. To this end, the dishwasher of the present invention comprises a case; a rack installed in the case for accommodating the dishes; a spray arm installed below the rack for spraying washing water; a combined circulation/drain pump including an upper pump for repeatedly pressurizing and supplying the washing water to the spray arm and a lower pump for discharging the washing water; and a filtering means for filtering the washing water, which includes a water collector formed below a bottom surface of the case and in a washing water flow passage connected to the combined circulation/drain pump, a filter provided in the water collector for filtering out garbage, a filter self-cleansing means for performing self-cleansing operation of the filter, a garbage collecting chamber that is provided below the bottom surface of the case and is connected to both a washing water discharge port of the upper pump and a drain flow passage of the lower pump, a fine filter mounted on a top surface of the garbage collecting chamber for filtering out the garbage from the washing water discharged upward, and a fine filter self-cleansing means for performing self-cleansing operation of the fine filter.
According to the dishwasher of the present invention, there is an advantage in that a user can more conveniently utilize the dishwasher, since the filtering means having the self-cleansing means installed therein is employed in the dishwasher.